American  Society  of  Municipal 
Improvements,  1915 


SPECIFICATIONS  FOR 

Sheet  Asphalt  Paving 

ADOPTED  OCTOBER  14,  1915 


These  specifications  will  be  modified  from  time  to  time 
to  keep  them  fully  up  to  date.  Suggestions  as  to  modifi- 
cations or  additions  are  solicited  and  should  be  sent  to 
the  Secretary,  or  to  Francis  P.  Smith,  131-3  East  23d 
St.,  New  York  City,  Chairman  of  the  Sub-Committee  on 
Specifications  for  Asphalt  Paving,  and  — 


GEORGE  W.  TILLSON 

Boro  Hall,  Brooklyn,  N.  Y. 
Chairman  of  General  Committee  on  Standard  Specifications 


COPYRIGHTED,  1916 

Any  municipality  which  is  represented  in  the  membership  of  the  society  by  one  or  more 
City  Officials  will  be  given  free  permission  to  use  these  specifications  or  any  part  of  them 
upon  application  to  the  Secretary. 


PUBLISHED  BY  THE  SOCIETY 
CHARLES  CARROLL  BROWN,  Secretary 

702  WULSIN  BUILDING 
INDIANAPOLIS,  INDIANA 


: 


c/ 


SPECIFICATIONS  FOR  SHEET  ASPHALT  PAVING. 

GENERAL  DESCRIPTION. 

1.  Upon  the  foundation  prepared  and  laid  as  elsewhere  herein 
specified,  shall  be  laid  the  pavement  proper.  This  shall  consist  of: 

1.  A  binder  course   .  .  .   inches  in  thickness  when  compressed. 

2.  An   asphalt   wearing  surface    .  .  .    inches   in   thickness   when 
compressed. 

MATERIALS. 

2.  The  materials  used  must  comply  with  the   requirements  of 
these  specifications  and  be  suitable  for  use  upon  the  street  or  streets 
to  be  paved.     They  shall  be  mixed  in  definite  proportions  by  weight, 
depending  upon  their  character,  and  the  traffic  upon  the  street,  and 
such  materials  and  proportions  must  be  satisfactory  to  the  Engineer. 

3.  Methods  of  Testing — All  tests  herein  specified  must  be  con- 
ducted according  to  official  methods  on  file  in  the  office  of  the  Engin- 
eer.    All    penetrations   at    77    degrees    Fahrenheit    are   expressed   in 
hundredths  of  a  centimeter  and  are  to  be  taken  (except  where  other- 
wise specified)  with  a  number  two  needle  acting  for  five  (5)  seconds 
without   appreciable   friction   under  a  total  weight  of  one   hundred 
(100)  grams. 

4.  Refined  Asphalts — The  refined  asphalts  admitted  under  these 
specifications    shall    be    prepared    from    a    natural    mineral    bitumen, 
either  solid  or  liquid,  or  from  combinations  thereof,  by  such  methods 
of  refining  as  will  produce  a  product  complying  with  the  require- 
ments hereinafter  given. 

The  preparation  and  refining  of  all  asphalts  admitted  under  these 
specifications  shall  be  subject  to  such  inspection  at  the  paving  plants 
and  refineries  as  the  Engineer  may  direct.  Every  refined  asphalt 
admitted  under  these  specifications,  if  required  by  the  Engineer,  shall 
be  equal  in  quality  to  the  recognized  standard  for  its  particular  kind 
or  type  of  asphalt.  If  desired,  the  Contractor  may  use  an  asphalt 
cement  prepared  at  the  refinery.  To  be  acceptable  this  asphalt  cement 
must  comply  with  the  foregoing  general  requirements  for  refined 
asphalt,  as  well  as  requirements  a,  b,  c,  d,  and  e  for  asphalt  cement. 


342331 


Asphalt  obtained  by  the  refining  of  natural  liquid  bitumens  shall 
not  be  reduced  in  the  refining  process  to  a  penetration  at  77  degrees 
F.  of  less  than  30. 

All  refined  asphalts  admitted  under  these  specifications  must 
comply  with  the  following  requirements: 

a.  All  shipments  of  refined  asphalt  of  any  one  kind  shall  have  the 
batch  number  plainly  marked  on  each  package  or  container  and  shall 
be  uniform  in  consistency  and  composition  and  shall  not  vary  from 
maximum  to  minimum  more  than  fifteen   (15)  points  in  penetration 
at  77  degrees  F. 

b.  Ninety-eight   and   one-half    (98^)    per  cent,    of    the    total 
bitumen  of  all  refined  asphalts  shall  be  soluble  in  carbon  tetrachloride. 

c.  When  made  into  an  asphalt  cement    by    the    use    of    such 
materials  and  methods  as  are  described  in  these  specifications,  they 
must  produce  an  asphalt  cement  complying  with  all  the  requirements 
elsewhere  set  forth  herein  for  asphalt  cements. 

5.  Fluxes — These  shall  be  the  residues  obtained  by  the  distilla- 
tion of  paraffine,  asphaltic  or  semi-asphaltic  petroleums.  They  shall 
be  of  such  character  that  they  will  combine  with  the  asphalt  to  be 
used  to  form  an  acceptable  and  approved  asphalt  cement  complying 
with  the  requirements  of  these  specifications.  All  residuums  must 
pass  the  following  general  tests: 

a.  They  must  have  a  penetration  greater  than  three  hundred  and 
fifty  (350)  with  a  No.  2  needle  at  77  degrees  F.  under  fifty  (50) 
grams  weight  for  one  second. 

b.  They  shall  have  a  specific  gravity  at  77  degrees  F.  between 
0.92  and  1.02. 

c.  When  twenty  (20)  grams  of  the  flux  are  heated  for  five  (5) 
hours  at  325   degrees  F.   in  a  tin  box  two  and  one-quarter    (2^) 
inches  in  diameter  and  three-quarters  (^4)  of  an  inch  deep  after  the 
manner  officially  prescribed,  the  loss  shall  not  exceed  five    (5)    per 
cent,  by  weight  and  the  residue  left  after  such  heating  shall  flow  at 
77  degrees  F. 

d.  They  shall  not  flash  below  350  degrees  F.  when  tested  in  a 
closed  oil  tester. 

e.  They  shall  be  soluble  in  carbon  tetra-chloride  to  the  extent 
of  not  less  than  ninety-nine   (99)   per  cent. 

6.  Binder  Stone — This  shall  be  clean,  hard,  broken,  stone,  free 
from  any  particles  that  have  been  weathered,  or  are  soft.  If  the 
stone  does  not  contain  the  proper  amount  of  material  passing  the  one- 


half  (*/2)  inch  screen,  the  deficiency  may  be  made  up  by  the  addition 
of  gravel  or  sand.  Ninety-five  (95)  per  cent,  of  the  binder 
aggregate  shall  pass  a  screen  having  circular  openings  whose  diameter 
shall  be  three-quarters  (ffl)  the  thickness  of  the  binder  course  to  be 
laid.  The  remaining  five  (5)  per  cent,  shall  not  exceed  in  their 
largest  dimension  the  thickness  of  the  binder  course  to  be  laid.  The 
binder  aggregate  shall  be  so  graded  from  coarse  to  fine  as  to  have 
the  following  mesh  composition  (sieves  to  be  used  in  the  order 
named)  : 
Passing: 

10    mesh 15  to  35%  1 

H-inch   circular   opening   and    retained  h  -      jl    PassmS  oco/ 

.,  -  ,  OA          er\cf     !  J/2          35      tO      OJ/C 

on    10    mesh    20  to  50y0  j       /2 

The  above  limits  as  to  mesh  composition  are  intended  to  provide 
for  such  permissible  variations  as  may  be  rendered  necessary  by  the 
available  sources  of  supply  and  the  character  of  the  work  to  be  done. 
The  mesh  composition  and  character  of  the  stone  may  be  varied, 
within  the  limits  above  specified,  at  the  discretion  of  the  Engineer, 
depending  upon  the  kind  of  asphalt  used  and  the  traffic  conditions 
upon  the  street  or  streets  to  be  paved. 

7:  Sand — The  sand  shall  be  hard,  clean  grained  and  moderately 
sharp.  On  sifting  it  shall  have  the  following  mesh  composition, 
(sieves  to  be  used  in  the  order  named)  : 

Passing: 

200  mesh 0  to     5%  Total       passing 

100  mesh  and  retained  on  200  mesh  10  to  25%  80    mesh    and 

80  mesh  and  retained  on  100  mesh  6  to  20%  retained        on 

50  mesh  and  retained  on     80  mesh  5  to  40%  200    mesh    20  to  40% 

40  mesh  and  retained  on     50  mesh  5  to  30% 

30  mesh  and  retained  on     40  mesh  5  to  25%  Total       passing 

20  mesh  and  retained  on     30  mesh  5  to  15%  10    mesh    and. 

10  mesh  and  retained  on     20  mesh  2  to  10%  retained        on 

8  mesh  and  retained  on     10  mesh  0  to     5%  40    mesh.  .12  to  45% 

On  very  light  traffic  streets  a  coarser  sand  may  be  used  with  the 
approval  of  the  Engineer,  but  in  no  case  shall  a  sand  be  employed 
that  contains  less  than  a  total  of  fifteen  (15)  per  cent,  passing  an 
80  mesh  sieve,  such  total  to  contain  not  more  than  five  (5)  per  cent, 
(calculated  on  the  original  sand)  passing  a  200-mesh  sieve,  or  a 
mixture  of  seventy-five  (75)  per  cent,  of  sand  of  the  character  above 
specified  and  twenty-five  (25)  per  cent,  of  stone  screenings  passing 
a  one-quarter  (^4)  inch  screen  and  retained  on  a  10-mesh  screen, 
may  be  employed. 

5 


The  above  limits  as  to  mesh  composition  are  intended  to  provide 
for  such  permissible  variations  as  may  be  rendered  necessary  by  the 
available  sources  of  supply  and  the  character  of  the  work  to  be  done. 
The  mesh  composition  and  character  of  the  sand  may  be  varied, 
within  the  limits  above  specified,  at  the  discretion  of  the  Engineer, 
depending  upon  the  kind  of  asphalt  used  and  the  traffic  conditions 
upon  the  street  or  streets  to  be  paved. 

Filler — This  shall  be  thoroly  dry  limestone  dust  or  dust  from 
other  equally  satisfactory  stone  or  Portland  cement,  the  whole  of 
which  shall  pass  a  30-mesh-per-linear-inch  screen  and  at  least  66  per 
cent,  of  which  shall  pass  200-mesh-per-linear-inch  screen.  The 
surface  mixture  shall  contain  from  6  to  20  per  cent,  of  this  filler, 
depending  upon  the  kind  of  sand  and  asphalt  used  and  the  traffic 
conditions  upon  the  street  or  streets  to  be  paved. 

8.  Samples — One    (1)    pound   samples   of   the   refined    asphalt, 
petroleum  flux  and  asphalt  cement  that  the  Contractor  proposes  to 
use  in  his  work,  together  with  a  statement  as  to  the  source,  character 
and  proportions  of  the  materials  composing  them,   must  be  handed 
in  with  his  bid  and  no  contract  shall  be  awarded  to  any  bidder  whose 
samples  do  not  comply  in  every  respect  with  these  specifications.     No 
asphalt  other  than  that  specified  in  his  bid  shall  be  used  by  any  Con- 
tractor except  with  the  written  consent  of  the  Engineer  and  provided 
that  it  complies  in  all  respects  with  the  requirements  of  these  speci- 
fications. 

In  addition  to  the  samples  submitted  with  the  bid,  other  samples 
taken  from  and  actually  representative  of  the  refined  asphalt,  petro- 
leum flux,  sand  filler  and  binder  stone  to  be  used  upon  the  street 
shall  be  submitted  to  the  Engineer  before  the  use  of  such  materials 
in  the  work  is  permitted.  Except  at  his  option,  no  work  on  binder 
or  Surface  shall  be  commenced  within  three  weeks  from  the  date 
when  such  samples  were  submitted  and  in  no  case  shall  they  be  used 
until  they  have  been  examined  and  approyed  by  him.  Whenever, 
during  the  course  of  the  work,  new  deliveries  of  paving  materials 
are  received  by  the  Contractor,  samples  of  these  shall  at  once  be  sub- 
mitted to  the  Engineer  and  their  use  in  the  \vork  will  not  be  per- 
mitted until  they  have  been  examined  and  approved  by  him. 

ASPHALT  CEMENT. 

9.  Preparation — The    asphalt    cement    shall     be     composed     of 
refined  asphalt,  or  asphalts  and  flux,  where  flux  is  required,  of  the 
character  elsewhere  herein  specified  and  must  be  of  a  suitable  degree 
of  penetration. 

6 


The  proper  proportions  of  the  refined  asphalt,  or  asphalts,  and 
flux,  shall  be  melted  together  at  a  temperature  between  275  and 
400  degrees  F.  and  thoroly  agitated  by  suitable  appliances  until 
they  are  completely  blended  into  a  homogeneous  asphalt  cement. 
Thereafter,  the  asphalt  cement  must  not  be  heated  to  a  temperature 
exceeding  350  degrees  F.  If  the  asphalt  cement  contains  material 
that  will  separate  by  subsidence  while  it  is  in  a  molten  condition,  it 
must  be  thoroly  agitated  before  drawing  from  storage  and  while 
in  use  in  the  supply  kettles.  Excessive  agitation  with  steam  or  air 
which  will  injure  the  cement  must  not  be  used. 

The  refined  asphalt  or  asphalts  and  flux  comprising  the  asphalt 
cement  shall,  when  required,  be  weighed  separately  in  the  presence 
of  the  authorized  inspectors  or  agents  of  the  Engineer. 

10.  Requirements — The   asphalt  cement  shall   comply  with  the 
following  requirements : 

a.  It  shall  be  thoroughly  homogeneous. 

b.  It  shall  have  a  penetration  at  77  degrees  F.  of  from  30  to  55 
for  heavy  traffic  streets  and  55  to  85  .for  light  traffic  streets  depend- 
ing upon  the  sand  and  asphalt  used  and  the  local  climate  conditions. 

c.  It  shall  not  flash  below  350  degrees    F.    when    tested    in?   a 
closed  oil  tester. 

d.  When  twenty   (20)   grams  of  the  asphalt  cement  are  heated 
for  five  (5)  hours  at  325  degrees  F.  in  a  tin  box  two  and  one-quarter 
(2%)   inches  in  diameter  and  three-quarters   (%)   of  an  .inch  deep, 
after  the  manner  officially  prescribed,  the  loss  shall  not  exceed  five 
(5)  per  cent,  by  weight  and  the  penetration  at  77  degrees  F.  of  the 
residue  left  after  such  heating  must  not  be  less  than  one-half  the 
penetration  at  77  degrees, F.  of  the  original  sample  before  heating. 

e.  Either  the  asphalt  cement  or  its  pure  bitumen  when  made 
into  a  briquette   (Dow  mold)   shall,  at  50  penetration   (77)   degrees 
F.),  have  a  ductility  of  not  less  than  30  'centimeters  at  77  degrees  F. ; 
the  two  ends  of  the  briquette  to  be  pulled  apart  at  the  uniform  rate 
of  5  centimeters  per  minute. 

When  the  asphalt  cement  as  used  has  a  penetration  other  than 
50  at  77  degrees  F.,  an  increased  ductility  of  2  centimeters  will  be 
required  for  every  five  points  in  penetration  above  50  penetration 
and  a  corresponding  allowance  will  be  made  below  50  penetration. 

BINDER. 

11.  Preparation — The    binder   shall    be   composed    of   stone,    or 
stone  and  sand,  and  asphalt  cement  of  the  character  elsewhere  herein 


specified  and  mixed  in  proper  proportions.  The  stone,  or  stone  and 
sand,  and  the  asphalt  cement  shall  be  heated  separately  to  such  a 
temperature  as  will  give,  after  mixing,  a  binder  of  the  proper  tempera- 
ture for  the  materials  employed.  The  stone  when  used  must  be  at  a 
temperature  between  225  and  350  degrees  F.  The  asphalt  cement 
and  stone  shall  be  thoroly  mixed  by  machinery  until  a  hom- 
ogeneous mixture  is  produced  in  which  all  the  articles  are  thoroly 
coated  with  asphalt  cement. 

12.  Laying — The  binder  mixture  prepared  in  the  manner  above 
described  shall  be  brought  to  the  work  in  wagons  covered  with  canvas 
or  other  suitable  material  and  upon  reaching  the  street  shall  have  a 
temperature  between  200  degrees  F.  and  325  degrees  F.  The  tem- 
perature of  the  binder  mixture  within  these  limits  shall  be  regulated 
according  to  the  temperature  of  the  atmosphere  and  the  working  of 
the  binder.  On  reaching  the  street  it  shall  at  once  be  dumped  on 
the  concrete  and  then  be  deposited  roughly  in  place  by  means  of  hot 
shovels,  after  which  it  shall  be  uniformly  spread  by  means  of  hot  iron 
rakes  and  then  at  once  be  thoroughly  compacted  by  tamping  or 
rolling.  The  thickness  of  the  finished  binder  shall  average  ... 
inches  and  not  more  than  forty  (40)  per  cent,  variation  from  the 
average  thickness  specified  will  be  permitted  at  any  one  spot.  The 
upper  surface  of  the  finished  binder  shall  be  parallel  to  the  established 
grade  for  the  finished  pavement.  The  surface  after  compression 
shall  show  at  no  place  an  excess  of  asphalt  cement  and  any  spot  show- 
ing such  excess  shall  be  cut  out  and  replaced  with  other  material. 
All  binder  that  shows  lack  of  bond  or  that  is  in  any  way  defective  or 
which  may  become  broken  up  before  it  is  covered  with  wearing 
surface  must  be  taken  up  and  removed  from  the  street  and  replaced 
by  good  material  properly  made  and  laid  in  accordance  with  these 
specifications,  at  the  expense  of  the  Contractor.  No  more  binder 
shall  be  laid  at  any  one  time  than  can  be  covered  by  one  day's  run 
of  the  paving  plant  on  surface  mixture.  Binder  when  laid  shall  be 
followed  and  covered  with  wearing  surface  as  soon  as  is  practicable 
in  order  to  effect  the  most  thoro  bond  between  the  binder  and 
the  wearing  course.  The  binder  course  shall  be  kept  as  clean  and  as 
free  from  traffic  as  is  possible  under  working  conditions.  If  necessary, 
it  must  be  swept  off  immediately  before  laying  the  wearing  surface 
on  it. 

No  binder  shall  be  laid  when  in  the  opinion  of  the  Engineer  the 
weather  conditions  are  unsuitable  or  unless  the  concrete  on  which  it 


is  to  be  laid  is,  even  though  damp,  free  from  pools  of  water  and  has 
set  a  sufficient  length  of  time. 

13.  Requirements — The  finished  binder  must  contain  four   (4) 
to  seven  (7)  per  cent,  of  bitumen  soluble  in  cold  carbon  disulphide, 
from  fifteen  (15)  to  thirty-five  (35)  per  cent,  of  material  passing  a 
10-mesh  screen,  and  from  twenty    (20)    to  fifty    (50)    per  cent,  of 
material   passing   a   one-half    (l/2)    inch   screen,    the   percentage    of 
bitumen  to  be  regulated  in  accordance  with  the  mesh  composition  and 
character  of  the  mineral  aggregate  of  the  binder  and  the  percentage 
of  material  passing  a   10-mesh  screen  to  be  regulated  in  accordance 
with  the  traffic  conditions  upon  the  street  or  streets  to  be  paved. 

WEARING  SURFACE. 

14.  Preparation — The   wearing   surface   shall    be    composed    of 
sand,   filler   and   asphalt  cement  of   the  character  elsewhere  herein 
specified  and  mixed  in  proper  and  definite  proportions  by  weight. 
The  sand  and  the  asphalt  cement  -shall  be  heated  separately  to  such 
a  temperature  as  will  give,  after  mixing,  a  surface  mixture  of  the 
proper   temperature   for   the   materials   employed.      The   sand   when 
used  must  be  at  a  temperature  between  275  and  400  degrees  F.    The 
asphalt  cement  when  used  must  be  at  a  temperature  between  250 
degrees  F.   and  350   degrees  F.     The  various  ingredients  shall  be 
brought  together  and  mixed   for  at  least  one  minute  in   a  suitable 
apparatus  until  a  homogeneous  mixture  is  produced  in  which  all  the 
particles  are  thoroughly  coated  with  asphalt  cement.     The  weights 
of  all  materials  entering  into  the  composition  of  the  wearing  surface 
shall  be  verified  in  the  presence  of  inspectors  as  often  as  may  be  re- 
quired and  the  Engineer  or  his  representatives  shall  have  access  to  all 
parts  of  the  plant  at  any  time. 

15.  Laying — The  surface  mixture  prepared  in  the  manner  above 
described  shall  be  brought  to  the  work  in  wagons  covered  with  can- 
vas or  other  suitable  material  and  upon  reaching  the  street  shall  have 
a  temperature  between  230  degrees  F.  and  350  degrees    F.      The 
temperature  of  the  surface  mixture  within  these  limits  shall  be  regu- 
lated according  to  the  temperature  of  the  atmosphere  and  the  working 
of  the  mixture  and  the  character  of  the  materials  employed.     On 
reaching  the  street  it  shall  at  once  be  dumped  on  a  spot  outside  of  the 
space  on  which  it  is  to  be  spread.     It  shall  then  be  deposited  roughly 
in  place  by  means  of  hot  shovels,  after  which  it  shall  be  uniformly 
spread  by  means  of  hot  iron  rakes  in  such  a  manner  that  after  having 


received  its  final  compression  by  rolling,  the  finished  pavement  shall 
conform  to  the  established  grade.  The  thickness  of  the  finished 
surface  mixture  shall  average  .  .  .  inches.  Not  more  than  a  ten  (10) 
per  cent,  variation  from  the  average  thickness  specified  will  be  per- 
mitted in  any  one  spot.  Before  the  surface  mixture  is  placed,  all 
contact  surfaces  of  curbs,  manholes,  etc.,  must  be  well  painted  with 
hot  asphalt  cement.  After  raking,  the  surface  mixture  shall  at  once 
be  compressed  by  rolling  or  tamping,  after  which  a  small  amount  of 
cement  shall  be  swept  over  it  and  it  shall  then  be  thoroly  com- 
pressed by  a  steam  roller  weighing  not  less  than  two  hundred  (200) 
pounds  to  the  inch  width  of  tread,  the  rolling  being  carried  on  con- 
tinuously at  the  rate  of  not  more  than  two  hundred  (200)  square 
yards  per  hour  per  roller,  until  a  compression  is  obtained  which  is 
satisfactory  to  the  Engineer.  Such  portions  of  the  completed  pave- 
ment as  are  defective  in  finish,  compression  or  composition,  or  that  do 
not  comply  in  all  respects  with  the  requirements  of  these  specifica- 
tions, shall  be  taken  up,  removed  and  replaced  with  suitable  material, 
properly  made  and  laid  in  accordance  with  these  specifications  at  the 
expense  of  the  Contractor.  Whenever  so  ordered  by  the  Engineer, 
a  space  of  twelve  (12)  inches  next  to  the  curb  shall  be  coated  with 
hot  asphalt  cement,  which  shall  be  ironed  into  the  pavement  with 
hot  smoothing  irons. 

No  wearing  surface  shall  be  laid  when  in  the  opinion  of  the 
Engineer  the  weather  conditions  are  unsuitable  or  unless  the  binder 
on  which  it  is  to  be  placed  is  dry.  Excessive  use  of  water  on  the 
steam  roller  when  compressing  the  pavement  will  not  be  permitted. 
The  finished  pavement  must  be  well  protected  from  all  traffic  by 
suitable  barricades  until  it  is  in  proper  condition  for  use. 

16.  Requirements — The  finished  pavement  shall  show  upon 
analysis  a  mesh  composition  and  bitumen  contents  within  the  follow- 
ing limits  (sieves  to  be  used  in  the  order  named)  : 

Bitumen    9.5   to   13.5%  f  Total       passing      200, 

Passing  200  mesh..  Not  less  than  10%  \      100     and     80    mesh. 

Passing  80  mesh    10  to  35%  [      Not  less  than 25% 

Passing  50  mesh    4  to  35%  f  Total    passing 

Passing  40  mesh    4  to  25%  \      50   and  40 

Passing  30  mesh    4  to  20%  [      mesh 15    to    50% 

Passing  20  mesh    4  to  12%  [  Total    passing 

Passing  10  mesh    2  to    8%  \      30,   20   and 

Passing  8  mesh    0  to    5%  [      10   mesh 10   to   35% 

The  minimum  amount  of  bitumen  shall  be  used  only  in  mixtures 
containing  the  minimum  total  passing  the  80  mesh.  The  percentage 

10 


of  bitumen  must  be  increased  above  the  minimum  as  the  total  passing 
the  80-mesh  increases.  On  streets  of  very  light  traffic,  when  the 
Engineer  has  approved  the  use  of  a  coarser  sand  or  mixture  than  that 
specified  for  general  use,  the  surface  mixture  must  contain  not  less 
than  six  (6)  per  cent,  of  mineral  matter  passing  a  200-mesh  sieve 
and  not  less  than  a  combined  total  of  eighteen  (18)  per  cent,  passing 
the  200,  100  and  80  mesh  sieves.  The  maximum  amount  of  200. 
100,  and  80  mesh  material  will  be  regulated  according  to  the  kind  of 
sand  and  asphalt  used  and  the  traffic  upon  the  street  on  which  the 
pavement  is  to  be  laid,  subject  to  the  maximum  requirements  else- 
where herein  specified  under  sand  and  filler. 

The  above  limits  as  to  mesh  composition  and  per  cent,  of  bitumen 
are  intended  to  provide  for  such  permissible  variations  'as  may  be 
rendered  necessary  by  the  raw  materials  used  and  by  the  character  of 
the  work  to  be  done.  The  composition  of  the  wearing  surface  may 
be  varied  within  the  limits  above  specified  at  the  discretion  of  the 
Engineer,  depending  upon  the  kind  of  sand,  filler  and  asphalt  used 
and  the  traffic  conditions  upon  the  street  or  streets  to  be  paved. 

CONDITION  AT  EXPIRATION  OF  GUARANTEE. 

17.  In  addition  to  the  proper  maintenance  of  the  pavement  dur- 
ing the  period  of  guarantee,  the  Contractor  shall,  at  his  own  expense, 
just  before  the  expiration  of  the  guarantee  period,  make  such  repairs 
as  may  be  necessary  to  produce  a  pavement  which  shall : 

a.  Have  a  contour  substantially  conforming  to  that  of  the  pave- 
ment as  first  laid  and  free  from  depressions  of  any  kind  exceeding 
one-half    (^2)    of  an   inch   in   depth   as  measured  between   any  two 
points    three  (3)  feet  apart  on  a  line  conforming  substantially  to  the 
original  contour  of  the  street. 

b.  Be  free  from  cracks  or  depressions  showing  disintegration  of 
the  surface  mixture. 

c.  Contain  no  disintegrated  surface  mixture. 

d.  Not  have  been  reduced  in  thickness  more  than  three-eighths 
of  an  inch  in  any  part. 

e.  Have  a  foundation  free  from  such  cracks  or  defects  as  will 
cause   disintegration   or  settling  of   the  pavement  or  impair   its  use- 
fulness as  a  roadway. 

REPAIRING. 

18.  Repairs,  except  as  provided  for  below,  shall  in  all  cases  be 
made  by  cutting  out  the  defective  binder  and  wearing  surface  down 

11 


to  the  concrete  and  replacing  them  by  new  and  freshly  prepared 
binder  and  wearing  surface  made  and  laid  in  strict  accordance  with 
these  specifications. 

Whenever  any  defects  are  caused  by  the  failure  of  the  foundation, 
the  pavement,  including  such  foundation,  shall  be  taken  up  and  relaid 
with  freshly  prepared  material  made  and  laid  in  strict  accordance 
with  these  specifications. 

In  all  cases  the  surface  of  the  finished  repair  shall  be  at  the  grade 
of  the  adjoining  pavement  and  in  accordance  with  the  contour  of  the 
street. 

The  surface  heater  method  of  repairing  may  be  used  only  in  those 
cases  where  the  repairs  are  not  rendered  necessary  by : 

a.  Fajlure  of  concrete. 

b.  Failure  of  the  binder. 

c.  Failure  caused  by  the  disintegration  of  the  lower  portion  of 
the  wearing  surface. 

Whenever  the  surface  heater  method  is  employed,  all  defective 
surface  shall  be  removed  before  replacing  it  with  new  material.  In  all 
cases  the  old  surface  shall  be  removed  to  a  depth  of  not  less  than  one- 
quarter  inch  and  the  new  surface  must,  when  conpressed,  be  not  less 
than  one-half  inch  in  thickness.  The  heat  shall  be  applied  in  such  a 
manner  as  not  to  injure  the  remaining  pavement.  All  burnt  and 
loose  material  shall  at  once  be  completely  removed  and,  while  the 
remaining  portion  of  the  old  pavement  is  still  warm,  shall  be  replaced 
by  new  and  freshly  prepared  wearing  surface  made  and  laid  in  strict 
accordance  with  these  specifications. 

19.  NOTE  TO  ENGINEERS — Filler — As  Portland  cement  is  more  expen- 
sive than  lime  dust,  the  specification  should  distinctly  state  which  kind  of 
filler  is  desired. 

Binder — The  following  clause  has  been  suggested  as  being  descriptive 
of  the  practice  in  some  cities.  The  committee,  however,  does  not  feel  like 
recommending  it  in  a  general  specification.  If  this  clause  is  incorporated 
in  the  specifications  it  should  be  clearly  stated  whether  or  not  the  practice 
described  therein  will  be  permitted  by  the  City  Engineer. 

With  the  permission  of  the  City  Engineer  not  to  exceed  twenty 
(20)  per  cent,  of  crushed  old  asphalt  surface  mixture  of  suitable 
character  may  be  used  in  combination  with  the  binder  stone,  pro- 
vided that  such  mixture  produces  a  binder  complying  in  all  respects 
with  the  requirements  of  these  specifications. 

12 


METHODS  FOR  TESTING  AND   SAMPLING. 

The  following  methods  are  recommended  as  being  sufficiently 
accurate  for  general  use.  In  cases  of  dispute  the  standard  methods 
adopted  by  the  American  Society  for  Testing  Materials  must  be 
employed. 

PENETRATION  TEST. 

20.  Penetrations  shall  be  taken  by  means  of  a  penetrometer, 
which  shall  be  so  constructed  as  to  correctly  register  in  one-hun- 
dredths  of  a  centimeter  the  depth  to  which  a  Robert's  Sharps  No.  2 
needle  will  penetrate  the  sample  under  examination  under  a  given 
load  without  appreciable  retarding  friction  for  a  given  time  period. 

For  penetrations  at  77  degrees  F.  the  time  period  shall  be  five 
(5)  seconds  and  the  total  weight  operating  on  the  needle  shall  be 
one  hundred  (100)  grams  except  in  the  case  of  flux  where  the  time 
period  is  one  (1)  second  and  the  total  weight  fifty  (50)  grams. 

The  samples  to  be  tested  should  preferably  be  in  circular  tin 
boxes  about  two  and  one-quarter  (2%)  inches  in  diameter  and  about 
three-quarters  (^4)  of  an  inch  deep  (2  ounce  Gill  style  can,  obtain- 
able from  the  American  Can  Company).  .  Where  very  soft  materials 
are  to  be  tested  or  penetrations  are  to  be  taken  at  100  degrees  F. 
or  115  degrees  F.,  a  tin  not  less  than  two  (2)  inches  deep  and  hav- 
ing the  same  diameter  specified  above  should  be  used  to  prevent  the 
needle  from  striking  the  bottom  of  the  tin  before  it  has  penetrated 
the  sample  to  the  full  depth. 

All  samples  shall  be  melted  at  a  temperature  just  high  enough 
to  render  them  liquid  (250  to  300  degrees  F.)  and  should  then  be 
thoroly  stirred  until  homogeneous  and  free  from  air  bubbles. 
After  cooling  sufficiently  in  the  air  at  laboratory  temperature  they 
must  be  immersed  for  at  least  thirty  (30)  minutes  in  water  main- 
tained at  the  temperature  at  which  the  test  is  to  be  made  (77  degrees 
F.).  During  testing  the  sample  shall  be  accurately  maintained  at 
the  temperature  specified. 

The  average  of  from  three  (3)  to  five  (5)  tests,  which  must  not 
differ  more  than  five  (5)  points  (five-hundredths  (0.05)  of  a 
centimeter)  between  maximum  and  minimum,  shall  be  taken  as  the 
penetration  of  the  sample,  the  needle  being  wiped  off  with  a  dry 
cloth  after  every  determination. 

13 


Remarks — This  test  measures  the  consistency  of  the  material  un- 
der examination.  The  limits  of  accuracy  of  this  test  may  be  con- 
sidered as  being  within  five  (5)  per  cent,  of  the  reading  obtained 
(above  or  below). 

DUCTILITY  TEST. 

21  This  test  is  usually  first  made  on  the  asphalt  cement  itself. 
If  this  fails  to  show  the  required  ductility,  the  pure  bitumen  must 
be  extracted  and  tested.  The  proper  methods  for  obtaining  the 
pure  bitumen  vary  with  the  asphalt  being  examined  and  are  too 
lengthy  for  description  here.  (See  proceedings  of  American  Society 
for  Testing  Materials,  Vol.  9,  pages  594-9.) 

Preparation  of  Briquette — The  molding  of  the  briquette  may  be 
done  as  follows: 

The  mold  should  be  placed  upon  a  brass  plate.  To  prevent 
the  asphalt  from  adhering  to  the  plate  and  the  inner  side  of  the 
two  removable  pieces  of  the  mold,  they  should  be  well  amalgamated. 
The  different  pieces  of  the  mold  should  be  held  together  in  a  clamp 
or  by  means  of  an  India  rubber  band.  The  material  to  be  tested  is 
poured  into  the  mold  while  in  a  molten  state,  a  slight  excess  being 
added  to  allow  for  shrinkage  on  cooling.  After  the  briquette  is 
nearly  cool,  it  is  smoothed  off  level  by  means  of  a  heated  palette 
knife.  When  cooled,  the  clamp  is  taken  off  and  the  two  side  pieces 
removed,  leaving  the  briquette  of  asphalt  firmly  attached  to  the  two 
ends  of  the  mold,  which  thus  serve  as  clips.  The  briquette  should 
be  immersed  in  water  maintained  at  the  required  temperature  for 
at  least  thirty  (30)  minutes  or  until  the  whole  mass  of  bitumen  is 
at  77  degrees  F.  It  is  then  pulled  apart  at  the  required  rate  of 
speed  in  a  suitable  machine,  the  briquette  being  entirely  immersed  in 
water  maintained  at  77  degrees  F.  during  the  entire  operation  of 
pulling.  Any  pieces  of  dirt,  wood,  or  extraneous  matter  in  the 
briquette  may  cause  the  fracture  of  the  fine  thread  before  the  true 
maximum  ductility  of  the  material  under  examination  has  been 
reached.  Great  care  should  be  observed,  therefore,  to  avoid  the 
presence  of  such  foreign  matter  in  the  bitumen  when  it  is  poured 
into  the  mold.  The  average  of  at  least  two  tests  shall  be  recorded 
as  the  ductility  of  the  sample  under  examination.  These  tests  must 
not  differ  more  than  twenty  (20)  per  cent,  from  their  average. 

Remarks — This  test  measures  approximately  the  cementing  value 
of  a  bitumen,  but  is  not  necessarily  a  measure  of  the  relative  cement- 

14 


ing  value  of  different  bituminous  materials  or  the  same  bituminous 
material  at  different  penetrations.  The  limits  of  accuracy  of  this 
test  may  be  considered  as  being  within  twenty  (20)  per  cent,  of  the 
reading  obtained  (above  or  below). 

DETERMINATION  OF  TOTAL  BITUMEN  IN  REFINED  ASPHALTS  AND 
ASPHALT  CEMENTS. 

22.  One  to  two  grams  of  the  sample  shall  be  weighed  into  a 
tared  200  c.  c.  wide-mouth  Erlenmeyer  flask  and  covered  with  100 
c.  c.  of  chemically  pure  carbon  disulphide.     Agitate  until  all  lumps 
disappear  and  nothing  adheres  to  the  bottom  of  the  flask.     Cork  and 
allow  to  stand  fifteen  (15)  minutes.     Filter  off  on  a  Gooch  crucible 
with   asbestos   felt  or  a  weighed  filter  paper  and    wash    until    the 
washings  come  thru  practically  colorless.     Dry  the  flask  and  filter 
at  250   degrees  F.     Evaporate  the  filtrate  containing  the  bitumen, 
burn  to  an  ash  and  add  to  the  residue  on  the  filter. 

Remarks — The  limits  of  accuracy  of  this  test  as  applied  to 
bitumens  containing  considerable  proportions  of  non-bituminous 
matter  may  be  considered  as  being  within  one-half  per  cent,  above 
or  below  the  result  obtained.  In  practically  pure  bitumens  one- 
quarter  (%)  per  cent,  above  or  below  is  the  ordinary  limit  of 
accuracy. 

DETERMINATION  OF  BITUMEN  SOLUBLE  IN  CARBON  TETRA- 

CHLORIDE. 

23.  One  gram  of  the  sample  shall  be  weighed  into  a  tared  200 
c.  c.  wide  mouth  Erlenmeyer  flask  and  covered  with   100  c.  c.  of 
chemically  pure  carbon  tetra-chloride.     Agitate  until  all  lumps  dis- 
appear and  nothing  adheres  to  the  bottom  of  the  flask.     Cork  and 
allow  to  stand  eighteen    (18)    hours  in   the  dark.     Filter  off  on  a 
Gooch  crucible  with  asbestos  felt  or  a  weighed  filter  paper  and  wash 
until  the  washings  come  thru   practically  colorless    using    not    less 
than   100  c.  c.  of  fresh  solvent.     Dry  the  filter  at  250  degrees  F. 

Remarks — The  amount  of  bitumen  insoluble  in  carbon  tetra- 
chloride  is  indicative  of  whether  or  not  decomposition  has  been 
produced  by  improper  heat  treatment.  The  limits  of  accuracy  of 
this  test  may  be  considered  as  being  within  one-half  (y2)  per  cent, 
above  or  below  the  result  obtained. 

15 


VOLATILIZATION  TEST. 

24.  Twenty    (20)    grams   of   the  sample   shall   be   placed   in   a 
weighed  tin  box  two  and  one-quarter  inches  in  diameter  and  three- 
quarters  of  an  inch  high   (two  ounce  Gill  style  can,  obtainable  from 
the  American   Can  Company)    and  heated  five    (5)    hours   at  325 
degrees  F.     The  heating  shall  be  done  in  a  ventilated  oven  which 
shall  have  reached  the  temperature  specified  before  the  introduction 
of  the  samples  and  which  is  maintained  within  two   (2)   degrees  of 
that    temperature    thruout    the    test.      The    tin    can    should    be    in- 
sulated by  a  sheet  of  asbestos  or  other  material  from  direct  metallic 
contact  with  the  sides  or  walls  of  the  oven.     The  bulb  of  the  ther- 
mometer should  be  immersed  in  a  control  bath  immediately  along- 
side of  the  sample  being  tested,  the  container  and  the  method  of  in- 
sulation being  the  same  in  both  cases. 

Remarks — This  test  indicates  the  extent  to  which  bitumens  in 
the  course  of  time  lose  their  more  volatile  hydro-carbon  constituents 
and  the  hardening  resulting  from  volatilization  and  chemical  change. 
It  may  be  considered  as  an  accelerated  exposure  test.  The  limits  of 
accuracy  of  this  test  cannot  be  definitely  stated  owing  to  the  widely 
varying  results  obtained  by  the  use  of  different  types  of  ovens  and 
failure  to  carefully  observe  all  the  conditions  prescribed.  When 
carefully  conducted  according  to  the  above  directions  a  test  showing 
six  (6)  per  cent,  loss  should  be  considered  as  passing  a  specification 
calling  for  not  over  five  (5)  per  cent.  loss. 

FLASH  TEST. 

25.  Flash  test  shall  be  made  in  a  circular  tin  can  about  two 
and  one-quarter   (2^4)   inches  in  diameter  and  about  one  and  three- 
eighths    (l^s)    inches  deep,    (3    ounce    Gill    style,    American    Can 
Company),  provided  with  a  suitable  transparent  cover  of  mica,  or 
glass,  etc.     This  cover  shall  be  provided  with  two  apertures  for  the 
insertion  of  the  thermometer  and  test  flame.     The  aperture  for  the 
thermometer  shall  be  three-eighths  (^)  of  an  inch  in  diameter  and 
shall  be  centrally  located.     The  aperture  for  the  test  flame  shall  be 
triangular  in  shape  measuring  one-half    (^2)    inch  on  the  base  and 
three  quarters  of  an  inch  in  height.     The  base  shall  coincide  with 
the   rim   of   the   can.      A   thermometer   approximately   fifteen    (15) 
inches   long,   graduated   in   single   degrees  shall   have   its   bulb   com- 
pletely immersed   in  the  material  being  tested.     It  shall  not  touch 
the  bottom  of  the  can  and  shall  be  suspended  in  the  proper  position. 

16 


The  can  shall  be  filled  with  the  material  to  be  tested  so  as  to  leave 
a  one-half.  (l/2)  inch  vapor  space  when  melted.  The  material  shall 
"be  he.ated  at  the  rate  of  ten  degrees  F.  a  minute  and  the  test  flame 
applied  every  five  degrees  F.  after  a  temperature  of  300  degrees  F. 
has  been  reached.  No  correction  for  emergent  stem  shall  be  made. 
The  test  flame  shall  be  one-eighth  (%)  of  an  inch  long  and  shall 
be  dipped  in  just  below  the  surface  of  the  cover  and  then  immedi- 
ately withdrawn. 

Remarks — This  test  indicates  the  temperature  at  which  inflam- 
mable vapors  are  given  off  in  an  enclosed  space.  It  supplements  the 
volatilization  test  and  guards  against  the  use  of  a  material  contain- 
ing too  large  an  amount  of  volatile  hydrocarbons.  The  limit  of  ac- 
curacy of  this  test  may  be  considered  as  being  five  (5)  degrees  above 
or  below  the  reading  obtained. 

SPECIFIC  GRAVITY  TEST. 

26.  a.     Fluid  Materials: 

The  specific  gravity  of  fluid  materials  shall  be  taken  in  the  usual 
way  in  a  picnometer  at  77  degrees  F. 

b.  Viscous  Fluid  and  Semi-Solid  Materials: 

The  specific  gravity  of  these  materials  shall  be  taken  in  a  cylin- 
drical weighing  bottle  picnometer  as  given  on  page  10,  bulletin  No. 
38  of  the  Office  of  Public  Roads. 

c.  Hard  Solid  Materials: 

The  specific  gravity  of  hard,  solid  materials  shall  be  taken  by  the 
displacement  method. 

DETERMINATION  OF  BITUMEN  CONTENTS  AND  MESH  COMPOSITION 

OF  BINDER. 

27.  Weigh  out  from  350  to  500  grams  of  the  binder  and  extract 
the  bitumen  from  it  in  a  centrifugal  extractor  or  suitable  continuous 
hot  extractor  using  chemically  pure  carbon  disulphide  as  a  solvent 
for  the  bitumen.     Follow  the  same  general  method  for  the  drying 
and  sifting  of  the  mineral  aggregate  as  described  in  the  method  for 
analyzing  surface  mixtures.     The  sieves  to  be  used  are  as  follows: 

1  i/2-inch,  1-inch,  2/J-inch  and  ^4-inch  circular  openings,  and  10- 
mesh. 

17 


Remarks — The  limits  of  accuracy  of  this  test  are  as  follows: 

For  bitumen  contents,  three-tenths  (0.3)  per  cent,  above  or. 
below  the  result  obtained.  For  mesh  composition,  ten  (10)  per* cent, 
of  the  result  obtained  (above  or  below). 


DETERMINATION  OF  BITUMEN  CONTENTS  AND  MESH  COMPOSITION 
OF  SURFACE  MIXTURES. 

28.  The  sample  of  surface  mixture  should  be  heated  to  about 
300  degrees  F.  until  soft  and  ten  to  twenty  grams  of  it  weighed 
on  to  a  tared  S.  &  S.  filter  paper  No.  595,  11  cms.  in  diameter.  The 
filter  paper  and  contents  should  be  placed  in  a  funnel  and  washed 
with  chemically  pure  carbon  disulphide  until  the  washings  run 
thru  practically  colorless.  Dry  the  filter  paper  and  residue  at 
250  degrees  F.  for  one-half  (^2)  hour.  Open  the  filter  paper  care- 
fully and  remove  the  mineral  aggregate.  Scrape  off  the  dust  adher- 
ing to  the  paper  as  thoroly  as  possible  with  a  blunt  palette  knife 
and  add  it  to  the  mineral  aggregate.  Evaporate  the  filtrate  con- 
taining the  bitumen,  burn  the  bitumen,  add  the  filter  paper  to  it 
and  burn  to  an  ash.  Add  the  ash  to  the  mineral  aggregate  previously 
removed  from  the  filter  paper  and  weigh.  The  difference  between 
the  weight  of  surface  mixture  originally  taken  and  the  combined 
weight  of  the  ash  and  residue  is  considered  as  the  weight  of  bitumen 
in  the  sample.  The  combined  ash  and  residue  is  then  sifted  through 
the  following  sieves  (in  the  order  named)  and  the  percentages  of 
the  various  sized  particles  calculated: 

200,  100,  80,  50,  40,  30,  20,  10  and  8. 

Sifting  shall  be  continued  on  each  sieve  until  less  than  one  (1) 
per  cent,  passes  thru  the  sieve  during  the  last  minute  of  sifting. 

If  desired,  the  surface  mixture  may  be  extracted  in  a  centrifuge 
or  in  any  suitable  form  of  extractor  with  hot  chemically  pure  carbon 
disulphide  and  the  combined  ash  from  the  extracted  bitumen  and 
the  mineral  aggregate  sifted  as  above. 

Remarks — The   limits  of   accuracy   of   this   test   are   as   follows: 
For   bitumen   contents,    three-tenths    (0.3)     per    cent,     above    or 
below   the   result   obtained.      For   mesh   composition,    ten    (10)    per 
cent,  of  the  result  obtained    (above  or  below). 

18 


SAMPLES. 

29.  Samples  should  be  put  in  clean,  dry  containers,  preferably 
tin  boxes  or  cans.  The  following  amounts  of  the  different  materials 
are  required  for  test: 

Binder   stone    5  pounds 

Filler Y  pound 


Sand  

Refined  asphalt 

Asphalt  cement 
Flux 


pound 
pound 
pound 
pound 

Method  of  Sampling — Extreme  care  should  be  taken  in  every  case 
to  obtain  a  sample  which  is  truly  representative  of  the  material  to 
be  examined.  These  samples  are  for  the  use  of  the  testing  labora- 
tory only  and  should  not  be  used  for  testing  at  the  plant  before  sub- 
mitting them  to  the  laboratory.  The  particular  precautions  to  be 
observed  in  each  case  are  given  below: 

Binder  Stone — A  sufficient  number  of  five-pound  samples  to  be 
taken  from  different  parts  of  the  pile.  These  should  be  thoroughly 
mixed  together  and  reduced  by  quartering  to  the  desired  size. 

Filler — A  sample  should  be  taken  from  several  bags  and  mixed: 

Sand — Samples  should  be  taken  from  the  interior  of  the  pile 
where  the  sand  is  damp.  A  sufficient  number  of  one  pound  samples 
to  be  taken  from  different  parts  of  the  pile.  These  should  be  thor- 
oly  mixed  together  and  reduced  by  quartering  to  the  desired  size. 

REFINED  ASPHALT  AND  ASPHALT  CEMENT. 

30.     In  barrels: 

At  least  one  sample  should  be  taken  from  each  batch.  It  should 
be  taken  at  sufficient  depth  below  the  surface  to  insure  obtaining 
representative  material  free  from  all  dirt  or  other  extraneous  matter, 
and  at  a  point  not  less  than  four  (4)  inches  distant  from  the  top  and 
sides  of  the  barrel. 

In  tank  cars: 

The  contents  of  the  tank  should  be  heated  until  completely  liquid 
thruout.  It  should  then  be  agitated  and  thoroly  mixed  by  means  of 
air  or  steam,  after  which  the  sample  shall  be  taken  from  the  dome 
in  such  a  manner  as  to  obtain  the  asphalt  from  a  point  at  least  three 
(3)  feet  below  the  surface. 

19 


In  kettles: 

The  contents  of  the  kettles  must  be  completely  liquid  and 
thoroly  agitated  previous  to  and  during  sampling.  The  sample  may 
be  taken  from  the  pipe  thru  which  the  material  is  delivered  to  the 
mixer  or  by  means  of  a  clean  dipper. 

31.  Flux — The    directions    given    for   sampling   refined    asphalt 
and  asphalt  cement  apply  to  this  material  except  that  under  ordinary 
conditions  it  is  nor  necessary  to  agitate  the  contents  of  the  tank  car. 

32.  Surface  and  Binder  Mixtures — Samples   should   preferably 
be  taken  on  the  street  after  the  mixture  has  been  shoveled  and  raked. 
Samples  taken  from  the  plant  shall  be  obtained   from  the  wagons, 
special  care  being  observed  to  avoid  material  from  the  top  of  the  load 
or  which   appears   to  vary  from   the   average.      Samples    should    be 
pressed  between  a  sheet  of  paper  and  trimmed  while  hot  to  a  con- 
venient size. 


A 


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